Psoriatic arthritis is an autoimmune disease. The immune system attacks healthy skin cells and joints, causing inflammation. Of the 7.5 million people with psoriasis, about 10%-30% get psoriatic arthritis.

What Is Stelara?

Stelara works differently from other medications that treat psoriatic arthritis, says Alice Gottlieb, MD, PhD, of Tufts Medical Center. She was the lead researcher on recent Stelara studies. The drug targets two proteins believed to play a role in psoriatic arthritis.

Gottlieb says it “acts like a microscopic sponge to sop up molecules that cause inflammation that lead to psoriasis and psoriatic arthritis.”

Stelara: Dosage, Studies

In the studies, 927 patients who had at least five tender and swollen joints, as well as other criteria, received Stelara injections. Some received a 45-milligram dose, while others received 90 milligrams. By week 24, about 44% to 50% of those getting the higher dose had at least a 20% improvement in signs and symptoms.

According to drugmaker Janssen Pharmaceuticals, Stelara may lower the ability to fight infections, including tuberculosis and other infections. It may decrease immune system activity and increase the risk of certain cancers, including skin cancers.

The wholesale cost of Stelara is $28,000 a year for the lower dose and $55,000 for the higher dose. Patients’ out-of-pocket costs would vary greatly depending on insurance coverage, according to a company spokesperson. Some patients with insurance may also qualify for the company’s instant savings program to help cover the cost of the drug.

The new approval is welcome news, says Soumya Reddy, MD, co-director of the Psoriasis and Psoriatic Arthritis Program at the NYU Langone Medical Center. “Patients who suffer from psoriatic arthritis have limited treatment options,” she says.

Gottlieb says although Stelara provides another treatment option, she would use other psoriasis drugs first. “More is known about them, and they have a longer safety record.”